Fig. 1. Modulation of Notch activity in mouse epidermis. (A) Anti-GFP (green) and anti-Jag1 (red) immunostaining with DAPI (blue) counterstain in a section of back skin anagen hair follicle of a TNR mouse. The bracket represents the pre-cortex, open arrows the outer root sheath, solid arrows the inner root sheath and asterisk the dermal papilla. (B,C) Tail epidermal whole mount of TNR mouse labelled with anti-GFP (green) antibody and DAPI (blue). (B) An optical transverse section at the position of the white line through z-stack images in C. The dashed line in B represents the basal epidermal surface. (D,E) Single plane images of wild-type tail epidermal whole mounts labelled with antibody to activated Notch (NICD) (D) or secondary antibody alone (E) (green) with DAPI (blue) counterstain. (F-H) Whole mounts of Jag1^flox/flox (F,G) and K5Cre Jag1^flox/flox (H) epidermis immunolabelled with anti-Jag1 antibody. The dashed lines indicate hair follicles and sebaceous glands. (G) Jagged 1 expression in the IFE. (I,J) Sections of Jag1^flox/flox (I) and K5Cre Jag1^flox/flox(J) hair follicles labelled with antibodies to keratin 14 (green) and cleaved Notch1 (red) and DAPI counterstain (blue). (K) Mouse keratinocytes transiently transfected with Hes1 luciferase reporter (Hes1-luc) alone or in combination with N^ICDOPER transgene and either treated with 4OHT (red bars) or untreated (blue bars). Data are expressed as average light units ±s.d., relative to the Renilla luciferase control. (L-O) Anti-ER immunostaining (red) with DAPI counterstain (green) of back skin from wild-type (L) or K14N^ICDOPER transgenic (M-O) mice treated with acetone (M) or 4OHT (L,N,O) for 1 hour. Scale bars: 50 µm in B,C,I,J,L-N; 100 µm in A-H. (P-R) Gross phenotype of 7.5-week-old K5Cre Jag1^flox/flox and Jag1^flox/flox littermates (P), and wild-type (Q) and K14N^ICDOPER (R) mice treated with 4OHT for 14 days. Insets in Q and R are higher magnification images of back skin.